Pitchfork was deemed suitable to be moved to an open prison last year following an assessment by probation officers and other specialists.

He is said to have made exceptional progress and is reportedly a model prisoner.

However, more than 20,000 people have signed an online petition, set up by Lynda’s family, calling for his release to be blocked.

A further 7,000 signed a paper version.

Police searching for clues in the murder case of Lynda Mann who was murdered on 21st November 1983 in Narborough, Leicestershire. Colin Pitchfork was convicted in January 1988 of the rape and murder of two young girls - Lynda Mann in 1983 and Dawn Ashworth in 1986. He was the first person convicted of a crime based on DNA fingerprinting evidence. 22nd November 1983.

The letter to the families states: “The offender is now progressing through the process and is reaching the next significant stage, which will be unescorted day release.

“This has been approved and the series of unescorted releases on temporary licence will be happening in the near future. There will be a robust risk management plan in place.”

In June, a Ministry of Justice spokesman said the department could not comment on individual cases.

However, a spokesperson said at the time: “All offenders must meet strict criteria and pass a full risk assessment before being onsidered for release on temporary licence (ROTL). ROTL is considered for offenders towards the end of their sentence, taking into account their individual resettlement needs. It helps build and maintain family ties, which is proven to help re-offending.

“Those who fail to comply with the conditions of a ROTL can be returned to closed prisons where they may have to serve additional time.”

Pitchfork lived in Newbold Verdon, attending school Market Bosworth and Desford, until his marriage in 1981 when he lived in Littlethorpe.

He was the first person in the world to be convicted on the basis of DNA evidence pioneered at the University of Leicester by Sir Alec Jeffreys.